[Rockingham]

Not true. According to the USGS (the U.S. Geological Survey), volcanic CO2 is less than one per cent of human CO2. See Volcanoes can affect the Earth's climate. and Volcanic Versus Anthropogenic Carbon Dioxide. The vast scale of human carbon dioxide production is unprecedented and intuitively troubling even though its relationship to ongoing natural climate variations remains in dispute.

[central_va]

intuitively troubling

To who? Since the beginning of the industrial revolution, CO₂ levels have gone from 200PPM to 400PPM which sounds like a huge increase but when you realize that there have been times when the earth's atmosphere contained over 2,000PPM CO₂ then the change seems insignificant. It is all relative. Also when the earth's atmosphere contained 2,000PPM CO₂ the earth was teaming with life and covered in lush jungles.